Re: [PATCH v2 1/3] KVM: X86: Trace vcpu_id for vmexit

[Sean Christopherson <sean.j.christopherson@intel.com>]

On Thu, Aug 15, 2019 at 06:34:56PM +0800, Peter Xu wrote:
> Tracing the ID helps to pair vmenters and vmexits for guests with
> multiple vCPUs.
> 
> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  arch/x86/kvm/trace.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
> index b5c831e79094..c682f3f7f998 100644
> --- a/arch/x86/kvm/trace.h
> +++ b/arch/x86/kvm/trace.h
> @@ -232,17 +232,20 @@ TRACE_EVENT(kvm_exit,
>  		__field(	u32,	        isa             )
>  		__field(	u64,	        info1           )
>  		__field(	u64,	        info2           )
> +		__field(	int,	        vcpu_id         )

It doesn't actually affect anything, but vcpu_id is stored and printed as
an 'unsigned int' everywhere else in the trace code.  Stylistically I like
that approach even though struct kvm_vcpu holds it as a signed int.

>  	),
>  
>  	TP_fast_assign(
>  		__entry->exit_reason	= exit_reason;
>  		__entry->guest_rip	= kvm_rip_read(vcpu);
>  		__entry->isa            = isa;
> +		__entry->vcpu_id        = vcpu->vcpu_id;
>  		kvm_x86_ops->get_exit_info(vcpu, &__entry->info1,
>  					   &__entry->info2);
>  	),
>  
> -	TP_printk("reason %s rip 0x%lx info %llx %llx",
> +	TP_printk("vcpu %d reason %s rip 0x%lx info %llx %llx",
> +		  __entry->vcpu_id,
>  		 (__entry->isa == KVM_ISA_VMX) ?
>  		 __print_symbolic(__entry->exit_reason, VMX_EXIT_REASONS) :
>  		 __print_symbolic(__entry->exit_reason, SVM_EXIT_REASONS),
> -- 
> 2.21.0
>